Phytopathogenic fungi are the casual agents for many diseases which infect and destroy agronomic crops. Especially devastating are leaf spot type diseases such as banana black sigatoka, sugar beet cercospora leaf spot and peanut leaf spot.
The leaves of the banana plant are subject to attack by a fungus, Mycosphaerella fijiensis, causing a disease called banana black sigatoka. Uncontrolled, banana black sigatoka kills the leaves of the banana plant, resulting in small, poor quality fruit. Because banana is a major export for many Latin American countries, the control of banana black sigatoka is critical to those countries' economies.
Currently, only five fungicide classes are used to treat banana black sigatoka. In some areas, the fungus has become resistant to the two most effective of those fungicide classes. The result has been more intensive spraying with the less effective fungicides. Therefore, there is a need for new fungicides with other modes of action for the continued protection of banana.
Sugar beet is susceptible to many foliar diseases caused by phytopathogenic fungi. One of the most frequently encountered and most destructive foliar diseases occurring on sugar beet is sugar beet cercospora leaf spot, caused by the fungus, Cercospora beticola. Sugar beet cercospora leaf spot is common to sugar beet throughout the world, but is most destructive in regions with wet, warm growing seasons, such as Western and Southern Europe, and the Midwestern United States. During periods of high temperature and wetness, sugar beet cercospora leaf spot increases rapidly in the field. This disease also kills leaf tissue resulting in reduced sugar beet weight and sugar content.
Peanut leaf spot, caused by fungi of the Mycosphaerella genus, is the most destructive foliar disease of peanut in the southeastern United States. Uncontrolled, peanut leaf spot causes the defoliation of entire files, resulting in reduced pod size and number. To date, management of peanut leaf spot has been problematic. Because of the development of resistance to fungicides, and the repeal of approval for other fungicides, ninety-nine percent of peanuts grown in this region are sprayed with a single fungicide. Accordingly, there is ongoing research to create new and more effective fungicides and methods for controlling or preventing such fungal infestations.
Certain quinazolinones have shown useful biological activity (see, e.g., M. T. Bogert and R. A. Gortner, J. Amer. Chem. Soc., 31, pp. 943-947 (1909); A. P. Bhaduri and N. M. Khanna, Indian J. Chem, 4, pages 447-449 (1966); and U.S. Pat. No. 3,696,102). None of these documents, however, refers to the use of quinazolinones as fungicides.
EP-A-360417-A published Mar. 28, 1990 relates to derivatives of 4-fluoroanthranilic acid and their use as fungicides. And, Y. A. Ammar, et al describe the antimicrobial activity of 6,8-dichloro-4-(3H)-quinazolinones in Current Science, 58, pp, 1231-1234 (1989). Neither of these documents, however, refers to the novel compositions and uses provided herein.
It is therefore an object of the present invention to provide 1-aryl-3-(3,4-dihydro-4-oxo-3-quinazolinyl)urea compounds that are highly effective for controlling or preventing phytopathogenic fungal infestations in agronomic crops, both growing and harvested.
It is also an object of the present invention to provide a method for the prevention, control or amelioration of a disease caused by a phytopathogenic fungus by contacting said fungus with a fungicidally effective amount of a 1-aryl-3-(3,4-dihydro-4-oxo-3-quinazolinyl)urea compound.
It is a feature of this invention to provide a method for the prevention, control or amelioration of leaf spot type diseases such as banana black sigatoka, sugar beet cercospora leaf spot and peanut leaf spot.
These and other objects and features of the invention will become more apparent from the detailed description set forth below.